High Resolution Wide Swath Repeat Acquisition SAR Imaging Mode and Algorithm with Near Space Platform

In this paper a short term repeat acquisition high resolution wide swath imaging mode with near space platform is proposed. The emission antenna is designed as linear phase steered array. It combined with proper receiving antenna mode forms one main lobe and two grating lobes, which provides the short term repeated visiting to the same imaged area. In order to get high azimuth resolution and wide swath, the echoes of the all sub beams are superimposed both in azimuth time and Doppler frequency domain. The paper proposes a multiple-channel multiple-beam reconstruction algorithm to separate them. The nonlinear chirp scaling algorithm is used to form the images of the sub beams. The performance parameters are analyzed as well. An example system design is given in this paper. The simulation results verify the validity and the correctness of the proposed imaging mode and the processing method. The calculated performance parameters show the qualities of the sub images satisfy the request of the applications.